Historical navigation routes in European waters leave their footprint on the contemporary seascape genetics of a colonial urochordate

Humans have intensively sailed the Mediterranean and European Atlantic waters throughout history, from the upper Paleolithic until today and centuries of human seafaring have established complex coastal and cross-seas navigation networks. Historical literature revealed three major long-lasting maritime routes (eastern, western, northern) with four commencing locations (Alexandria, Venice, Genoa, Gibraltar) and a fourth route (circum-Italian) that connected between them. Due to oceangoing and technological constraints, most voyages were coastal, lasted weeks to months, with extended resting periods, allowing the development of fouling organisms on ship hulls. One of the abiding travellers in maritime routes is the colonial ascidian Botryllus schlosseri already known since the eighteenth century in European and Mediterranean ports. This species, was almost certainly one of the common hull fouling travellers in all trade routes for centuries. Employing COI haplotypes (1008 samples) and microsatellite alleles (995 samples) on colonies sampled from 64 pan-European sites, present-day Botryllus populations in the Mediterranean Sea/European Atlantic revealed significant segregation between all four maritime routes with a conspicuous partition of the northern route. These results reveal that past anthropogenic transports of sedentary marine species throughout millennia long seafaring have left their footprint on contemporary seascape genetics of marine organisms.


Appendix Tables 1-16
Appendix Table 1 "During the second half of the eighteenth century, the Mediterranean had started experiencing a come-back in the Western European economy and by the mid-nineteenth century the Mediterranean had become one of the busiest and most important commercial arteries of Europe and the world" (page 298).
While before the eighteen century the number of commercial vessels that sailed between the Mediterranean and the Baltic Sea was limited to about 50/year (see section 6 below), "the number of merchant vessels departing from the Baltic Sea for Mediterranean ports shows an upward trend, at least as regards the earlier part of our period with the number of vessels increasing from 157 in 1784, to 243 vessels in 1787, falling to an average of around 200 vessels per annum for the years 1788-1791, before climbing to 234 vessels in 1792" (page 300).During the period 1784 to 1795, 2057 (171/year) vessels arrived to the Baltic from the Twenty most important Mediterranean Trading Ports for the Baltic (page 301).This reference further reveals that maritime trajectories between the Baltic and the Mediterranean were almost exclusively with the Spanish, French and Italian ports of the Western Mediterranean (pages 301-302)."On the whole, the success of the measures taken in 1654 to increase maritime traffic in Genoa was undeniable; the level of traffic entering the port rose to 1,013,530 cantari* in 1654 and 1,285,700 in 1655, compared to an average of roughly 718,000 cantari for the three preceding years.35The figure of 985,500 cantari for 1656 would in all probability have been much higher, even surpassing that of the previous two years, if the plague had not broken out in June of that year, bringing port traffic to a halt.There can be no doubt concerning which of the 1654 innovations contributed most to the dramatic increase in port traffic.In 1655 only eight of the 396 merchant ships entering the port took part in the convoy organized by the state, and participation in the convoys diminished during the following years.The republic continued to organize convoys for nearly thirty years, but they were no longer presented as an alternative to the free port for increasing maritime traffic."*1cantaro =50 kg (approximately).

Lopez RS (1964) Market Expansion:
The Case of Genoa.The Journal of Economic History 24, 445-464.
This source details the directions of the Genovese shipping: Eastwards westwards and southwards.Although both, Venice and Genova maintained long term naval connections with the levant, the black sea countries and even established a colony in Crimea.However, "Genoa lies farther from the Levant and Africa than her two major medieval rivals, Venice and either Pisa or Pisa's heir, Florence; but she has the best location for trade in the western Mediterranean.Here, Barcelona alone was for some time a serious competitor, and that time was before the fifteenth century.We have seen that the western Mediterranean, not the Levant, was the earliest focus of Genoese trade ." (page 456)."The Phoenicians did not have the compass or any other navigational instrument, and so they relied on natural features on coastlines, the stars, and dead-reckoning to guide their way and reach their destination.
The most important star to them was the Pole Star of the Ursa Minor constellation and, by way of a compliment to their sea-faring skills, the Greek name for this group was actually Phoenike or 'Phoenician'.Some maps of coastal stretches are known to have existed but were unlikely to have been used during a voyage.Rather, navigation was achieved through the position of the stars, sun, landmarks, direction of the winds, and the experience of the captain of tides, currents and winds on the particular route being taken.Close to shore, Herodotus mentions the use of sounding leads to measure the sea depth, and we know that Phoenician ships had a crow's nest for greater visibility."Genoa to the levant in the 14 th century.One trip lane was in areas of sight of land for most of the time and the other all the time.

13.
Masson P (1967, first published 1896) Histoire du Coerce Français dans le Levant au XVIIIe Siecle, N.Y., Burt Franklin, pp.407 -417.This source describes an intensive trade between the Levant and Southern European ports in France (Marseilles, Toulon, Languedoc) established already in the 17 th century and onwards (pages 355-502).14.Van der Wee, H (1990) Structural changes in European long-distance trade, and particularly in the re-export trade from south to north, 1350-1750.In: James D. Tracy (ed.)The Rise of Merchant Empires Long-Distance Trade in the Early-Modern World, 1350-1750.Cambridge, Cambridge University Press, pp.19-20.Summary: At the end of the 13 th century the first Italian galleys from Venice, Florence and Genoa left the Mediterranean for northwestern Europe, going mainly to Bruges Antwerp and London.During the 14 th and 15 th centuries this direct maritime that connected between Italy and the North Sea ports became a regular one, replacing to some extent the overland trade via France.The expansion of the north-south maritime trade stimulated commercial activity in ports along the new sea route: the ports of Catalonia, Mallorca and Valencia and of Andalusia, Portugal and the French Atlantic coast benefitted from the galleys moving northward (more details in footnote 8).15.Cartwright, M. (2016).The Phoenicians Master Mariners.World History Encyclopedia.Retrieved from https://www.worldhistory.org/article/897/the-phoenicians---master-mariners/ 9 in page 128 shows the visibility of land from the sea.2) Map 12 in page 141 shows two trips from

.
Sampling sites of B. schlosseri populations used in the present study.In bold: current study.In bold and Italics-sites where only microsatellites were analyzed.E=eastern route; W= western route; N= northern route; C=circum-Italian route.

Table 2 .
COI haplotypes used for the study with accession numbers.

Table 3 .
Fisher Exact using COI haplotypes test results for the four navigation routes.1= eastern, 2=circum Italian, 3= western, 4= northern.The same holds for all the Tables 3-9.

Table 4 .
Route 1 vs. Route 2 significance results.a. 12 cells (66.7%) have expected count less than 5.The minimum expected count is .40. b.Based on 100000 sampled tables with starting seed 1487459085.
Appendix Table5.Route 1 vs. route 3 significance results.a. 13 cells (59.1%) have expected count less than 5.The minimum expected count is .31. b.Based on 100000 sampled tables with starting seed 1421288173.Appendix Table6.Route 1 vs. route 4 significance results.a. 6 cells (27.3%) have expected count less than 5.The minimum expected count is 1.10 b.Based on 100000 sampled tables with starting seed 1122541128.

Table 8 .
Route 2 vs. route 4 significance results a. 10 cells (45.5%) have expected count less than 5.The minimum expected count is .20. b.Based on 100000 sampled tables with starting seed 745618922.Appendix Table 9. Route 3 vs.route 4 significance results.a. 7 cells (31.8%) have expected count less than 5.The minimum expected count is .46. b.Based on 100000 sampled tables with starting seed 205597102.

Table 14 .
Bs811 microsatellite locus effect size and significance results on SPSS 351 cells (88.6%) have expected count less than 5.The minimum expected count is .13.aMicrosatellite haplotypes Frequencies and Sample Size by route .

Textiles with the Mediterranean Basin, 1200-1600: A Cost-Benefit Analysis of Comparative Advantages in Overland and Maritime Trade Routes. International Journal of Maritime History, Vol. XI, No. 2 1-30
As early as c. 1274, the Genoese had made the first direct maritime contact with Flanders; and by 1317 the Italians had instituted a fairly regularannual galley service to Bruges.The Venetians, after founding their Bruges consulate in 1322 and establishing a maritime link with Southampton, came to dominate that northern galley trade.

Pourchasse P (2011) Trade between France and Sweden in the Eighteenth Century. Forum navale 67, 92-114.
The seventeenth century was to witness a deep structural change in the nature of the Mediterranean trade.The overwhelming majority of grain shipments made from northern Europe to the Mediterranean region during the famines of the 1590s were sent in northern European ships.As Fernand Braudel and many other historians have pointed out, the previously sporadic presence of English and Dutch ships and merchants in the Mediterranean was intensified during the 1590s.22Having thus established a presence in the Mediterranean, a great number of northern ships that had arrived carrying foodstuffs remained for relatively long periods, engaging in the rich infra-Mediterranean trades." "